The U.S. space shuttle Discovery has undocked from the International Space Station and is returning to Earth, ending its nine-day stay at the orbiting outpost.

Discovery pulled away from the space station Wednesday. The shuttle's crew is using a laser-tipped boom to inspect the craft's wings and nose before returning home.

Discovery and its seven-member crew, which includes a Japanese astronaut, is scheduled to land back on Earth Saturday.

The astronauts arrived at the space station last week to deliver and attach a $1 billion Japanese laboratory. They also tested a robotic arm that will help with science experiments outside the station.

Discovery's commander, Mark Kelly, says the mission was a great success.

Astronaut Garrett Reisman is returning to Earth on the shuttle after spending three months aboard the space station. His replacement, Greg Chamitoff, will remain on the station for six months.